Title: Effect of Particle Size Distribution of Sand on Mechanical Properties of Cement Mortar Modified with Microsilica

Author(s): Kawan Ghafor, Wael Mahmood, Warzer Qadir, and Ahmed Mohammed

Publication: Materials Journal

Volume: 117

Issue: 1

Appears on pages(s): 47-60

Keywords: curing time; microsilica; modeling; statistical analysis; strengths; water-cement ratio (w/c)

DOI: 10.14359/51719070

Date: 1/1/2020

Abstract:
Despite the many research studies on the effect of the particle size distribution (PSD) of sand and microsilica content on the mechanical properties of cement mortar, there has not been a comprehensive study investigating the effect of the PSD curve corresponding to 10% of fines, microsilica content, curing time, and watercement ratio (w/c) on the compressive, tensile, and flexural strengths of cement mortar. Therefore, this study investigates the subject, which could be beneficial for geotechnical, building, and construction fields. In this study, more than 1000 data on the mechanical properties of the cement mortar modified with different percentages of microsilica, varied from 5 to 55% (by dry weight of the cement), were collected from the literature. The statistical analysis, modeling, and nonlinear regression analysis were performed on the collected data. The w/c ranged between 0.2 and 0.8. The Vipulanandan p-q Model was used and compared to the Logistic Growth Model to predict the PSD of sands used in cement mortar. The Vipulanandan Correlation Model was also used and compared with the Hoek-Brown Model to correlate the mechanical properties of cement mortar modified with microsilica. The Vipulanandan Correlation Model has a lower root mean square error (RMSE) compared to the Hoek-Brown Model. The results of the present study showed that there is a good relationship between the compressive strength with flexural strength and tensile strength for cement mortar modified with microsilica. Based on the coefficient of determination (R2) and RMSE, the compressive strength, flexural strength, and tensile strength of cement mortar quantified well as a function of w/c, the microsilica content (MS %), curing time, and effective diameter d10 using nonlinear relationship.